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Mechanical properties of paddy soils in relation to their moisture content
92
ABSTRACTS
51. I. V. Frurakis and V. I. Mininzon. Investigating a composite tractor hydraulic motor. Trakt. Selkhozmash., 1963, 33 (8) 9-12; bibl. 3, illus. (R.) A composite low-speed hydraulic motor is described, consisting of a 3 high-speed axial-piston motors with working volumes of 0.032 l/rev and having gear wheels engaging the final drive, which gives three ranges of operation depending on the number of component motors connected in parallel. Investigations were made to determine the characteristics of the motor, and the effect of various methods of connecting the motors in series and in parallel. It is concluded that a composite motor with mechanical disengagement and automatic changing of ranges in relation to loading is most suitable for tractors. (N.I.A.E.) 52. A. M. Gurevieh and S. P. Koikov. The operation of Belarus tractors on balloon tyres. Mekhaniz. Elektrif sots. seL Khoz., 1964, 22 (3) 54-55; illus. (R.) Balloon tyres 1420 × 500, 1500 × 600 and 1500 × 840 mm (replacing 12 × 38 tyres) on 50 hp tractors increased traction and were especially effective on loose soil of up to 25 % m.c. and on snow. (N.I.A.E.) 53. V. V. Guskov. Choice of optimum parameters of future track-laying tractors. Trakt. Selkhozmash 1963, 33 (8) 5-8; illus. (R.) Relationships are plotted between characteristics and weight of tractors on stubble on sand, loam and peat bog and a nomogram compiled relating specific ground pressure, max. B.D. pull, bearing surface of the tracks and specific D.B. pull. 4 general-purpose and 3 marsh-land tractors are planned of 36-200 and 135-250 hp with 0.6-5 and 3-10 ton D.B. pulls and 0"55--0-36 and 0-22-0.18 kg/cm z specific ground pressures. (N.I.A.E.) 54. J. Hmler. Soil compressibility and its determination (in German), Schweiz. Bauzig. 82, 41, 709-716, Oct. 1964. This report contains four essential chapters: (1) Determination of compressibdity by means of oedometer, (2) Its determination in situ, (3) Compressibility of compacted soil, (4) Use of triaxial apparatus. There is also a discussion of effects of nonhomogeneous compressibility on building stability and on resulting structural damages. (Applied Mechanics Review) 55. C. J. Jaw and P. K. Lu. Mechanical properties of paddy soils in relation to their moisture content. Actapedol. sin., 1964, 12, 132-142 (Ch.e.) The mechanical strength of paddy soil at different m.c. was determined in laboratory experiments with simulated rice and wheat stubbles and recommendations for the ploughing of paddy soil under rice stubble were based on the results. (N.I.A.E.) 56. K. V. Klementev and V. I. Bulbo. An experiment in measuring the hydraulic pressures in the pipelines of hydraulic systems. Trakt. Selkhozmash., 1963, 33 (8) 34-36; illus. (R.) Electronic equipment and quick-response capacitance gauges were used with oscillographs to measure pulses up to 100, 300 and 500 kg/cm z in the hydraulic system of a grab loader (see 1964, abstr. 2019). (N.I.A.E.) 57. G. G. Koiol~v. Experimental investigation of the distribution of specific pressures in the contact of a pneumatic tractor tyre with the soil. Trakt. Selkhozmash., 1960, 30 (12) 15-18; bibl. 9, illus. (R.) A 37 hp tractor was tested on a seedbed, stubble and concrete at 4-56 km/h with inflation pressures of 1 "75, 1-25, 1 -0 and 0-75 atm. Half-shaft torque, wheel revolution, time, D.B. pull, radial deformation of the tyre carcase and depth of rut were recorded and pressure gauges were used to measure pressures on the bearing surface of the tyre and on the tread bars. (N.I.A.E.) 58. R. L. Koadner and R. J. Krizek. Creep compliance response of a cohesive soil. J. Franklin Inst. 279, 5, 366-373, May 1965. Paper presents a method of representing data from unconfined compression tests of cohesive soils in which a constant stress t~0 is applied and the creep strains e (t) measured over a period of time. Following approaches used in linear viscoelastic theory, the stress-strain relationships are expressed in the form of a creep compliance J (t) where J(t)=e(t)/co. If the soil is nonlinear, the creep compliance will also be a function of t~0. Tests on one soil show nonlinearity. An assumed form for e (t) is proposed and by curve fitting methods the expression for J(t,ao) is
ABSTRACTS
51. I. V. Frurakis and V. I. Mininzon. Investigating a composite tractor hydraulic motor. Trakt. Selkhozmash., 1963, 33 (8) 9-12; bibl. 3, illus. (R.) A composite low-speed hydraulic motor is described, consisting of a 3 high-speed axial-piston motors with working volumes of 0.032 l/rev and having gear wheels engaging the final drive, which gives three ranges of operation depending on the number of component motors connected in parallel. Investigations were made to determine the characteristics of the motor, and the effect of various methods of connecting the motors in series and in parallel. It is concluded that a composite motor with mechanical disengagement and automatic changing of ranges in relation to loading is most suitable for tractors. (N.I.A.E.) 52. A. M. Gurevieh and S. P. Koikov. The operation of Belarus tractors on balloon tyres. Mekhaniz. Elektrif sots. seL Khoz., 1964, 22 (3) 54-55; illus. (R.) Balloon tyres 1420 × 500, 1500 × 600 and 1500 × 840 mm (replacing 12 × 38 tyres) on 50 hp tractors increased traction and were especially effective on loose soil of up to 25 % m.c. and on snow. (N.I.A.E.) 53. V. V. Guskov. Choice of optimum parameters of future track-laying tractors. Trakt. Selkhozmash 1963, 33 (8) 5-8; illus. (R.) Relationships are plotted between characteristics and weight of tractors on stubble on sand, loam and peat bog and a nomogram compiled relating specific ground pressure, max. B.D. pull, bearing surface of the tracks and specific D.B. pull. 4 general-purpose and 3 marsh-land tractors are planned of 36-200 and 135-250 hp with 0.6-5 and 3-10 ton D.B. pulls and 0"55--0-36 and 0-22-0.18 kg/cm z specific ground pressures. (N.I.A.E.) 54. J. Hmler. Soil compressibility and its determination (in German), Schweiz. Bauzig. 82, 41, 709-716, Oct. 1964. This report contains four essential chapters: (1) Determination of compressibdity by means of oedometer, (2) Its determination in situ, (3) Compressibility of compacted soil, (4) Use of triaxial apparatus. There is also a discussion of effects of nonhomogeneous compressibility on building stability and on resulting structural damages. (Applied Mechanics Review) 55. C. J. Jaw and P. K. Lu. Mechanical properties of paddy soils in relation to their moisture content. Actapedol. sin., 1964, 12, 132-142 (Ch.e.) The mechanical strength of paddy soil at different m.c. was determined in laboratory experiments with simulated rice and wheat stubbles and recommendations for the ploughing of paddy soil under rice stubble were based on the results. (N.I.A.E.) 56. K. V. Klementev and V. I. Bulbo. An experiment in measuring the hydraulic pressures in the pipelines of hydraulic systems. Trakt. Selkhozmash., 1963, 33 (8) 34-36; illus. (R.) Electronic equipment and quick-response capacitance gauges were used with oscillographs to measure pulses up to 100, 300 and 500 kg/cm z in the hydraulic system of a grab loader (see 1964, abstr. 2019). (N.I.A.E.) 57. G. G. Koiol~v. Experimental investigation of the distribution of specific pressures in the contact of a pneumatic tractor tyre with the soil. Trakt. Selkhozmash., 1960, 30 (12) 15-18; bibl. 9, illus. (R.) A 37 hp tractor was tested on a seedbed, stubble and concrete at 4-56 km/h with inflation pressures of 1 "75, 1-25, 1 -0 and 0-75 atm. Half-shaft torque, wheel revolution, time, D.B. pull, radial deformation of the tyre carcase and depth of rut were recorded and pressure gauges were used to measure pressures on the bearing surface of the tyre and on the tread bars. (N.I.A.E.) 58. R. L. Koadner and R. J. Krizek. Creep compliance response of a cohesive soil. J. Franklin Inst. 279, 5, 366-373, May 1965. Paper presents a method of representing data from unconfined compression tests of cohesive soils in which a constant stress t~0 is applied and the creep strains e (t) measured over a period of time. Following approaches used in linear viscoelastic theory, the stress-strain relationships are expressed in the form of a creep compliance J (t) where J(t)=e(t)/co. If the soil is nonlinear, the creep compliance will also be a function of t~0. Tests on one soil show nonlinearity. An assumed form for e (t) is proposed and by curve fitting methods the expression for J(t,ao) is